Dementia and the Senses

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Dementia and the Senses

What you need to know about dementia’s effect on the five senses

As we age, many different changes occur in the body, including changes in the sensory organs that enable us to see, to hear, to touch, to smell and to taste.

With some modifications to the environment and dietary adjustments, most people can adapt.

However, for people with dementia, these sensory changes are confusing, stressful, and can put the person’s safety at great risk.  

Vision changes

  • Pupils size becomes smaller and slower to constrict which creates problems with glare. Reflection of light on anything shiny is too stimulating and a falls risk (Meisami, Brown and Emerle, 2003)
  • Slowness of pupils to dilate in the dark creates difficulty in seeing where one is going
  • Visual acuity is less sharp in dim lights, sees shadows, shapes
  • In dementia, the field of vision can narrow to 12 inches around, almost like wearing binoculars. This means the person has a very limited line of sight. If they cannot see it, it does not exist
  • When brain processes information that is too stimulating, it reacts by shutting down information from one eye leaving the person with dementia to see with one eye (monocular vision). This loss of depth perception and contrast sensitivity results in the person with dementia doing strange things e.g. exaggerated stepping, picking at air (Snow, 2016)
  • Colour agnosia reduces ability to differentiate between colours of similar dark or light tones therefore hard to identify objects that are set against a background consisting of similar colours
  • Most people with dementia find vision changes the most difficult to deal with because the brain does not understand and process the picture/image it is receiving


  • Wear glasses
  • Clear demarcation between floors, walls, toilet and wall/floor
  • Remove throw rugs, clutter to create clear pathways
  • Low glare light/automatic lights indoors and outdoors
  • Avoid busy patterns, checkerboard or zigzag designs
  • Appropriate footwear, use mobility aide

Hearing changes

  • Auditory canal narrows, cerumen glands atrophy causing thicker, dryer ear wax that is more difficult to remove and increases hearing impairment
  • Everyday sounds can become too loud, too stimulating, creating distortion in what the person with dementia hears/understands
  • Problems with hearing and ear pain will have an impact on person’s ability to concentrate on eating. An interesting study found a correlation between development of ear wax and reduced ability to chew among people who did not have their back teeth (Frasman, 2005)
  • Many people with dementia have difficulty chewing and this may increase susceptibility to impacted earwax, pain and hearing loss
  • Difficulty hearing/understanding creates feelings of isolation and frustration


  • Clean ears daily, assist with hearing aids
  • Regular visits to doctor and dentist
  • Reduce noise in person’s environment
  • Avoid crowded, busy, noisy areas as too stimulating for person to process
  • Face person when talking, speak slowly and clearly, write down message, show item

Touch changes

  • Tactile sensitivity decreases because of skin changes and loss of large numbers of nerve endings particularly in fingertips, palms of hands and lower extremities (Meisami, 1995)
  • Skin becomes thinner and more susceptible to open areas increasing risk of infection
  • Inability to distinguish between hot and cold
  • Decreased nerve endings reduce pain sensitivity, feelings of soreness and discomfort. e.g. pressure ulcer
  • For some people, any touch to the skin is painful e.g. in the shower, water feels like needles


  • Inspect skin and nails, especially toes, look for sores, areas of redness, bluish hues, areas of extreme cold/warm
  • Identify hot and cold faucets, reduce temperature in hot water tank
  • Wear footwear indoors/outdoors, wear mittens in cold weather
  • Ensure sharp corners are padded e.g. table

Sense of smell

  • Studies have shown that an impaired sense of smell is one of the earliest symptoms of Alzheimer’s and Parkinson’s disease
  • Of all the senses, age takes the greatest toll on smell perception
  • Changes in smell are attributed to loss of cells in the olfactory bulbs of the brain and a decrease in sensory cells in the nasal lining
  • Unable to detect smoke, leaking gas, spoiled food


  • Install smoke detectors and gas detector
  • Write expiry dates on food, check fridge contents weekly

Sense of taste

Taste, along with smell and nerve stimulation determine flavour of foods and helps distinguish between safe and harmful foods.

  • With age, there is atrophy of the taste buds and decrease in saliva production
  • As taste buds diminish and insulin in the brain drops, many people with dementia experience changes in appetite and can overuse salt, spices, sugar
  • Studies have shown when dementia attacks part of the brain responsible for self-restraint in diet, unhealthy cravings increase (Sauer, 2014)
  • Unable to identify food by taste, including mouldy food, sour milk
  • May eat toothpaste, mouthwash, household cleaners mistaking them for food


  • Remove medications, toiletries, cleaning items
  • Limit access to salt, sugar, junk food
  • Wear properly fitting dentures, perform good oral care
  • Remove any small objects that resemble candies/food
  • Use saliva substitutes, encourage fluids
  • See dietician for meal suggestions

The sixth sense
People with dementia, even if unable to communicate, still have an awareness of the world around them, and they can sense when someone is being unkind or disrespectful.

"They may forget what you said, they may forget what you did, but they will never forget how you made them feel." (Maya Angelou).